U.S. patent number 11,148,798 [Application Number 16/015,760] was granted by the patent office on 2021-10-19 for engine and rotatable proprotor configurations for a tiltrotor aircraft.
This patent grant is currently assigned to Textron Innovations Inc.. The grantee listed for this patent is Textron Innovations Inc.. Invention is credited to David Russell Bockmiller, George Ryan Decker, Colton Gilliland, James Kooiman, Eric Stephen Olson, Mark Przybyla, Michael E. Rinehart, Clegg Smith, Jeffrey Williams.
United States Patent |
11,148,798 |
Gilliland , et al. |
October 19, 2021 |
Engine and rotatable proprotor configurations for a tiltrotor
aircraft
Abstract
A tiltrotor aircraft includes a propulsion system with a fixed
engine and a rotatable proprotor. The engine is located on the top
surface of the wing of the tiltrotor aircraft, and the rotatable
proprotor assembly is also mounted on the top surface of the wing.
The engine and proprotor assembly are connected via a series of one
or more gearboxes that route the engine output from the engine to
the proprotor.
Inventors: |
Gilliland; Colton (Northlake,
TX), Williams; Jeffrey (Hudson Oaks, TX), Rinehart;
Michael E. (Euless, TX), Kooiman; James (Fort Worth,
TX), Przybyla; Mark (Keller, TX), Smith; Clegg (Fort
Worth, TX), Olson; Eric Stephen (Fort Worth, TX), Decker;
George Ryan (Mansfield, TX), Bockmiller; David Russell
(Fort Worth, TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
Textron Innovations Inc. |
Providence |
RI |
US |
|
|
Assignee: |
Textron Innovations Inc.
(N/A)
|
Family
ID: |
68981372 |
Appl.
No.: |
16/015,760 |
Filed: |
June 22, 2018 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20190389572 A1 |
Dec 26, 2019 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64C
3/56 (20130101); B64C 29/0033 (20130101); B64D
35/00 (20130101) |
Current International
Class: |
B64C
29/00 (20060101); B64D 35/00 (20060101); B64C
3/56 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
United States Patent and Trademark Office, U.S. Appl. No.
13/966,678, filed Aug. 14, 2013, 31 pages. cited by
applicant.
|
Primary Examiner: Badawi; Medhat
Attorney, Agent or Firm: Whitaker Chalk Swindle &
Schwartz PLLC Sanchez; Enrique
Claims
What is claimed is:
1. A propulsion system for a tiltrotor aircraft, comprising: an
engine disposed on a wing, wherein the engine comprises an output
shaft along an engine longitudinal axis, and wherein the wing
comprises a leading edge, a trailing edge, a top surface and a
bottom surface and a central axis that runs substantially parallel
to the leading edge and the trailing edge; a rotatable proprotor
assembly disposed on the top surface of the wing, wherein the
proprotor assembly comprises a proprotor pylon, a rotor mast, a
plurality of rotor blades coupled to the rotor mast, and a
proprotor input operable to accept a drive force generated by the
output shaft, and wherein the rotor mast and plurality of rotor
blades are disposed around a common proprotor longitudinal axis; a
first gearbox disposed in a drive path between the output shaft and
the proprotor input, wherein the first gearbox is operable to
transfer a drive, force from the output shaft to the proprotor
input; and a wing extension attached directly to the wing, below
the proprotor assembly and engine, wherein the engine longitudinal
axis is above, and substantially perpendicular to, the central axis
of the wing, wherein the proprotor pylon contains the engine, and
wherein a wing interconnect included at a center of the wing allows
the wing to be removably attached to a fuselage of the tiltrotor
aircraft such that the wing to be removed or rotated to allow the
tiltrotor aircraft to be stored or shipped in a shipping
container.
2. The propulsion system of claim 1, wherein the proprotor pylon is
disposed on the top surface of the wing and connects the proprotor
assembly to the wing, and provides for at least a 90.degree.
rotation of the proprotor assembly about the central axis of the
wing.
3. The propulsion system of claim 1, further comprising a second
gearbox, wherein the first gearbox is an engine reduction gearbox,
and the second gearbox is proprotor gearbox.
4. The propulsion system of claim 3, further comprising an
interconnect drive system, the interconnect drive system
comprising: an interconnect gearbox disposed between the engine
reduction gearbox and the proprotor gearbox; an interconnect drive
shaft coupled to the interconnect gearbox, wherein the interconnect
drive shaft is operable to transfer drive force from the propulsion
system of claim 3 to a second propulsion system disposed on one of
the same wing or a second wing, wherein the interconnect drive
shaft runs substantially along the longitudinal axis of the wing
from the coupling of the interconnect drive shaft at the
interconnect gear box, and wherein the interconnect gearbox is
operable to direct at least a portion of the drive force to the
interconnect drive shaft.
5. The propulsion system of claim 4, wherein the interconnect
gearbox transfers at least a portion of the drive force from the
engine reduction gearbox to the proprotor gearbox.
6. The propulsion system of claim 5, wherein: the engine generates
an output drive along the engine axis; the engine reduction gearbox
changes the direction of the output drive at least 90.degree. so
that the output drive is routed to the interconnect gearbox; the
interconnect gearbox routes output drive to a proprotor gearbox
input; and the proprotor gearbox converts the output drive to a
rotating engine output along a longitudinal axis of the proprotor
assembly.
7. The propulsion system of claim 6, wherein the rotating engine
output is directed to the rotor mast and rotor blades along the
proprotor longitudinal axis.
8. The propulsion system of claim 7, wherein the proprotor
longitudinal axis and the engine longitudinal axis are
substantially parallel when the tiltrotor aircraft is operating in
an airplane mode.
9. The propulsion system of claim 7, wherein the proprotor
longitudinal axis and the engine longitudinal axis are
substantially normal when the tiltrotor aircraft is operating in a
helicopter mode.
10. The propulsion system of claim 7, wherein the engine
longitudinal axis is fixed and the proprotor longitudinal axis is
rotatable from 0.degree. to at least 90.degree. relative to the
engine longitudinal axis.
11. A tiltrotor aircraft, comprising: a fuselage having a
longitudinal axis, a tail section, at least two wings, and at least
two propulsion systems, wherein the at least two propulsion systems
are disposed opposite each other relative to the fuselage, wherein
the at least two wings comprise, respectively, a leading edge, a
trailing edge, a top surface, a bottom surface, and a central axis
substantially normal to the fuselage; and wherein the at least two
propulsion systems comprise, respectively: an engine having an
engine longitudinal axis, the engine disposed above the central
axis of the wing, wherein the engine longitudinal axis is
substantially normal to the central axis of the wing; a proprotor
assembly having a proprotor longitudinal axis disposed on a pylon
mounted on the top surface of the wing, wherein the proprotor
longitudinal axis is substantially normal to the central axis of
the wing, and wherein the proprotor longitudinal axis is rotatable
in relation to the central axis of the wing from a position
substantially parallel to the engine longitudinal axis to a
position substantially normal to the engine longitudinal axis,
wherein the proprotor assembly comprises a rotor mast and a
plurality of rotor blades mounted thereon; an engine reduction
gearbox disposed between an engine output shaft and a proprotor
input, the at least one gearbox operable to transfer the drive
force generated by the engine to the proprotor assembly to turn the
rotor mast; wing extensions attached directly to the wings below
the proprotor assembly and engine; and a wing interconnect disposed
between the two wings, wherein the wing interconnect is operable to
removably attach the wings to the fuselage, wherein the pylon
contains the engine, and wherein the wing interconnect allows the
wings to be removed or rotated to allow the tiltrotor aircraft to
be stored or shipped in a shipping container.
12. The tiltrotor aircraft of claim 11, further comprising an
interconnect drive system, wherein the interconnect drive system is
connected to the engine output shaft, and mounted in a position
fixed relative to the engine, and comprises: an interconnect
gearbox disposed between the engine reduction gearbox and the
proprotor input; and an interconnect drive shaft coupled to the
interconnect gearbox of each of the at least two propulsion systems
along the longitudinal axes of the two wings, wherein the
interconnect gearbox is operable to transfer at least a portion of
an output drive generated by the engine to the interconnect drive
shaft and the proprotor input of each of the at least two
propulsion systems.
13. The tiltrotor aircraft of claim 12, further comprising a
proprotor gearbox operable to change the direction of the output
drive at the proprotor input to the longitudinal axis of the
proprotor.
14. The tiltrotor aircraft of claim 11, wherein the at least two
wing extensions are operable to removably couple to each of the
respective wings.
15. The tiltrotor aircraft of claim 11, wherein the proprotor
assembly is positioned distal the fuselage to maximize a turn
radius of the rotors disposed on the rotor mast, wherein the engine
is positioned directly below the proprotor assembly to maximize the
lift area of the wing.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to engine and proprotor configurations for
tiltrotor aircraft.
2. Background of the Invention
The present invention relates to wing-mounted engines for aircraft.
In a typical configuration, to maximize efficiency, the engine and
proprotor are configured linearly, whereby the engine has a
straight shaft that drives the rotor or propeller. More recently,
some aircraft have been developed, such as the V-22 Osprey by Bell
Helicopter Textron Inc., that features an engine and proprotor that
may be rotated 90.degree. so that the aircraft is capable of
vertical take-off and landing (VTOL).
While the V-22 is an extremely successful design for a multi-use
aircraft, the mechanical requirements of the engine, proprotor, and
wing make storage and maintenance of the aircraft difficult. One
improvement to the V-22 design includes a fixed engine with a
rotating proprotor as shown in U.S. patent application Ser. No.
13/966,678. In the '678 Application, the engine is fixed at the end
of the wing, outboard of die proprotor. While an improvement to
locate the engine and proprotor at the end of the wing distal from
the fuselage, this configuration limits the ability to incorporate
wing extensions outboard of the engine. Additionally, the engine of
the '678 Application is located on the wing axis, which, limits the
amount of lift that may be generated from the wing, because the
length of the wing and therefore the lift surfaces of the wing are
reduced by the width of the engine. Another drawback of the '678
Design is that the inboard location of the proprotor limits the
diameter of the propeller, and the outboard location of the engine
limits the ability to break down the wing for storage.
Based on the foregoing, there is a need for an alternative
configuration of a tiltrotor aircraft proprotor and engine that
maximizes the surface area of the aircraft wing, and allows
flexibility for engine and proprotor placement to minimize the
space needed for storage and/or shipment of the tiltrotor
aircraft.
SUMMARY OF THE INVENTION
In accordance with the present invention, the engine is therefore
fixed above the top surface of the wing, and the pylon and
proprotor assembly are also located above the wing, preferably
outboard of the engine. This configuration provides added
flexibility for storage while maximizing the lift generated by
allowing a greater bottom surface of the wing for lift.
Additionally, the configuration shown takes the engine out of the
wing central axis, thereby reducing the stress on the wing
structure. By mounting the proprotor pylon and engine above the
wing, wing extensions may be added on the outboard side of the
propulsion system, thereby further increasing the lift and reducing
fuel consumption to allow for longer flight duration. The wing
extensions may be removable or foldable to aid in storage and/or
transportation of the tiltrotor aircraft.
To facilitate the separate placement of the fixed engine and
rotatable proprotor, one or more gearboxes may be placed in the
drive line from the engine output shaft to the proprotor input. In
this manner, the direction of the drive shafts may be altered to
facilitate flexibility in the placement of the engine and
proprotor. Additionally, an interconnect drive system may be
included, such that an interconnect drive shaft connects the engine
on one side of the aircraft to the proprotor on the other side of
the aircraft in the event of a loss of power by one engine. This
interconnect drive system may include a gearbox that facilitates
the change in direction of the engine output drive to accommodate
the separation of the engine and proprotor in various
configurations.
BRIEF DESCRIPTION OF THE DRAWINGS
The novelty of the features described herein are set forth in the
claims. Additionally, the systems and methods claimed are supported
by the drawings of certain embodiments, which are referenced in the
detailed description, and are shown as follows.
FIG. 1 is a perspective view of a tiltrotor aircraft m helicopter
mode, according to the prior art '678 Application;
FIG. 2 is a perspective view of a tiltrotor aircraft in airplane
mode, according to the prior art '678 Application;
FIGS. 3A-3D show various views of a tiltrotor aircraft in
accordance with the present invention;
FIG. 4--shows an engine and proprotor configuration in accordance
with the present invention;
FIG. 5 shows an engine and proprotor configuration without a wing
obstructing the view of the various components;
FIG. 6 shows an embodiment of a tiltrotor aircraft in a storage
container.
DETAILED DESCRIPTION OF THE INVENTION
The disclosure below includes several illustrative embodiments of
the system of the present invention. In the interest of clarity,
all of the features of the systems are not described in detail, but
would be apparent to one of ordinary skill in the art as being a
requirement to build a fully functioning design implementing the
novel inventions disclosed. Numerous implementation-specific
decisions would necessarily be made during the design and
construction of an aircraft that meets the goals of the builder. I
should be apparent that while any development effort might be
complex and time-consuming, it would be routine for one or more of
ordinary skill in the art.
The specific special relationships of various components are not
described in detail, as those represent design variations
well-within the level of skill in the art.
FIGS. 1 and 2 show a tiltrotor aircraft in accordance with a prior
art fixed-engine design, but is nevertheless useful in describing
the improvements disclosed herein. FIG. 1 shows a tiltrotor
aircraft 101 in helicopter configuration, and FIG. 2 shows a
similar tiltrotor aircraft 101 in airplane configuration. The
tiltrotor aircraft 101 includes a fuselage 103, landing gear 105, a
tail section 107 (which may be a "v-tail" as shown in FIGS. 1 and
2, or any other suitable tail section configuration, as is known in
the art), one or more wings 109, and propulsion systems 111 and 113
on either end of wing 109. It should be understood that in the
prior art, as well as in the present invention, the wing 109 may be
a single wing 109 that is affixed atop fuselage 103, or may be
comprised of one or more sections 109 on either side of fuselage
103 and a wing connector 110 that connects wings 109 to fuselage
103. Wing 109 includes a leading edge, a trailing edge, a top
surface and a bottom surface.
At the outboard edge of wing 109, each propulsion system 111 and
113 include an engine 123 and a proprotor assembly, or proprotor
pylon, 115. The proprotor assembly includes rotor blades 119
affixed to a rotor mast 117. As shown in FIGS. 1 and 2, engine 123
includes an inlet 141 and may include an engine cowling 139. The
proprotor assembly has a longitudinal axis 160, and is rotatable
from 0.degree. to 90.degree. or more, where 0.degree. is
substantially parallel to a longitudinal axis 150 of engine 123 and
90.degree. is substantially parallel to engine axis 150.
In the prior art configuration described above, the engine 123 and
proprotor assembly 115 are located with the engine outboard of the
proprotor assembly 115. This configuration is problematic because
the engine is generally in the same plane as the center axis of the
wing 109, thereby reducing the potential surface area of wing 109.
Additionally, because the wing 109 terminates in the proprotor
assembly 115, the configuration limits the ability to add any wing
extensions on the engine nacelle distal from the fuselage because
the engine location disrupts the structural integrity of the wing
relative to an extension.
FIGS. 3A-3D show various views of a tiltrotor aircraft in
accordance with embodiments of the present disclosure. The
tiltrotor aircraft 201 includes a fuselage 203, landing gear 205
(not shown), a tail section 207, and a wing or wings 209. Fuselage
203 defines a longitudinal axis 390. Wing 209 defines a central
longitudinal axis 380. The embodiment shown includes a propulsion
system 211 that includes an engine 223 mounted above the top
surface of wing 209 and a proprotor assembly 215 mounted above the
lop surface of wing 209. It will be understood that while only one
propulsion system 211 is described in detail, in various
embodiments, the tiltrotor aircraft 201 would include corresponding
propulsion systems 211 on either side of the aircraft. Engine 223
defines a longitudinal axis 350, and proprotor assembly 215 defines
a longitudinal axis 360. In various embodiments, the tiltrotor
assembly 215 is rotatable from a position of 0.degree. to at least
90.degree., where 0.degree. is measured by the respective
longitudinal axes 350 and 360 of the engine 223 and proprotor
assembly 215 being substantially parallel, and 90.degree. is
measured by the longitudinal axis 360 of the proprotor assembly 215
being substantially perpendicular to the engine axis 350. Proprotor
assembly 215 includes a proprotor pylon 221, proprotor mast 217 and
rotor blades 219 attached thereto. Additionally, wing extensions
230 may be attached to the structure of wing 209 below the
proprotor assembly.
FIGS. 4 and 5 show a detailed view of the propulsion system 211
from a top view and a perspective view, respectively. The
propulsion system 211 comprises engine 223 and proprotor assembly
215. Engine 223 may include a nacelle 239, inlet 241, and an output
shaft 242. Engine output shaft 242 transfers engine output drive
(shown in bold arrows) from engine 223 to one or more gearboxes
that terminates at proprotor assembly 215, in the embodiment shown,
the engine output shaft 242 connects to an engine reduction gearbox
310, which in turn routes the engine output drive to an
interconnect drive system 320 that is more fully described in U.S.
patent application Ser. No. 13/966,678. The interconnect drive
system 320 may include an interconnect gearbox 322 that further
routes the engine output drive to the proprotor gearbox 330, which
is part of the proprotor assembly 215, and converts the engine
output drive to a rotating engine output along proprotor assembly
longitudinal axis 360 to proprotor mast 217. Additionally, the
interconnect drive system 320 includes an interconnect drive shaft
326 along an interconnect drive axis 324 that connects the engine
output drive from one propulsion assembly 211 to another propulsion
assembly 211 on the same aircraft. In a preferred embodiment, the
interconnect drive shaft is contained within the body of wing 209
and connects to a corresponding interconnect drive system 320 on
another propulsion assembly 211.
The propulsion system 211 also includes a conversion actuator 340
that is operable to rotate the proprotor assembly 214 about
conversion axis 370 from 0.degree. to at least 90.degree..
It should be noted that the various gearboxes serve to route the
engine output drive behind the leading edge of wing 209. This
routing is preferred but not required. However, by routing the
interconnect drive system 320 in the aft section of wing 209, it
permits the proprotor gearbox 330 and engine reduction gearbox 310
to be located closer to the leading edge of the wing 209, where
there is more structural stability. Additionally, when routing the
engine output drive inboard of the proprotor assembly 215 toward
leading edge of wing 209, it permits attachment of wing extensions
230 to the wing structure of wing 209.
An additional benefit of the propulsion system configuration shown
herein is the storability of tiltrotor aircraft 201. Because the
engine 223 and tiltrotor assembly 215 allow maximum lift surface of
wing 209, the entirety of wing 209 may be removed and/or rotated to
a position wherein the central axis of wing 209 is substantially
parallel to fuselage longitudinal axis 390. This configuration
allows for tiltrotor aircraft 201 to be stored and or shipped in a
standard 40' shipping container 400, as shown in FIG. 6. To
facilitate the removal and/or rotation of wing 209 relative to
fuselage 203, a wing interconnect 210 may be included at the center
of wing 209 adjacent to fuselage 203. The wing interconnect allows
the wing 209 to be removably attached to the fuselage 203.
The particular embodiments disclosed in this description are
intended to be illustrative of, and not limiting to, the novel
concepts of the invention as claimed below. Changes, alterations,
additions, or omissions may be implemented without departing from
the spirit and scope of the invention, including operation of the
system using some, more, or less than all of the components shown
and described. No limitations are intended to be placed on the
disclosure of the invention, except as claimed below. Other claims
may be supported by the description herein, and no waiver of such
claims is hereby made. It is not the intention of the inventors to
invoke the paragraph (f) of 35 U.S.C. .sctn. 112 unless the words
"means for" and "function" are used explicitly in a particular
claim.
* * * * *